1. Field of the Invention
The present invention relates to an apparatus for driving a lens in a camera.
2. Description of Related Art
A lens of a camera is moved in an optical axis direction by a predetermined or desired displacement, in accordance with purposes thereof, such as zooming or focusing, etc. As a lens driving apparatus, especially for the zooming operating usually a cam type of driving apparatus is used which has a circular an cylindrical cam ring coaxial with the lens and a lens holder which is supported for movement in the optical axis direction. The cam ring has cam grooves in which cam follower pins provided on the lens holder are fitted, so that when the cam ring is manually or electrically rotated, the lens holder, holding the lens, can be moved in the optical axis direction in accordance with the cam profile of the cam grooves.
There is no particular problem with the operation per se of the lens driving apparatus. However, the cam ring a component is not only expensive, but also makes it difficult to realize a thin lens driving apparatus. In particular, in case where the lens holder has a non-circular projection which is not coaxial to the lens, the diameter of the cam ring is made larger, thus resulting in a large lens driving apparatus. Furthermore, the cam follower pins provided on the lens holder extend in the radial direction of the lens, and accordingly, the cam grooves formed in the cam ring extend also in the radial direction, so that the cam grooves must be individually machined.